The term "polyphenylene ether" resin is descriptive of a well known group of polymers that may be made by a variety of catalytic and non-catalytic processes. By way of exemplification, certain of the polyphenylene ethers are disclosed in Hay, U.S. Pat. Nos. 3,306,874 and 3,306,875, and in Stamatoff, U.S. Pat. No. 3,257,357 and U.S. Pat. No. 3,257,358. In the Hay patents, the polyphenylene ethers are prepared by an oxidative coupling reaction comprising passing an oxygen-containing gas through a reaction solution of a phenol and a metal-amine complex catalyst. Other disclosures relating to processes for preparing polyphenylene ethers are set forth in Fox, U.S. Pat. No. 3,356,761; Sumitomo, U.K. Pat. No. 1,291,609; Bussink et al, U.S. Pat. No. 3,337,499, Blanchard et al, U.S. Pat. No. 3,219,626; Laakso et al, U.S. Pat. No. 3,342,892; Borman, U.S. Pat. No. 3,344,166; Hori et al, U.S. Pat. No. 3,384,619; Faurote et al, U.S. Pat. No. 3,440,217 and disclosures relating to metal based catalysts which do not include amines are known from patents such as Wieden et al., U.S. Pat. No. 3,442,885 (copper-amidines); Nakashio et al, U.S. Pat. No. 3,573,257 (metal alcoholate or phenolate); Kobayashi et al, U.S. Pat. No. 3,455,880 (cobalt chelates); and the like. In the Stamatoff patents, the polyphenylene ethers are produced by reacting the corresponding phenolate ion with an initiator such as a peroxy acid salt, an acid peroxide, a hypohalite, and the like, in the presence of a complexing agent. Disclosures relating to noncatalytic processes, such as oxidation with lead dioxide, silver oxide etc. are described in U.S. Pat. No. 3,382,212. Cizek, U.S. Pat. No. 3,383,435 discloses compositions of polyphenylene ethers and styrene resins.
In Czechoslovakian patent 165,110 there are described compositions of a polyphenylene ether resin; polystyrene or high impact polystyrene; and either an ethylene-propylene copolymer, polyisobutylene or an .alpha.-olefin copolymer. U.S. Pat. No. 3,943,191; U.S. Pat. No. 4,101,503; U.S. Pat. No. 4,101,504; U.S. Pat. No. 4,101,505 and U.S. Pat. No. 4,102,850 all disclose compositions that include a polyphenylene ether resin and an alkenyl aromatic resin that is modified with an interpolymerized EPDM rubber. All of the above-mentioned patents are incorporated herein by reference.
The applicants have found that when a composition of a polyphenylene ether resin and a triaryl phosphate or a composition of a polyphenylene ether resin and an EPDM modified alkenyl aromatic resin is combined with an ethylene propylene rubber, there results a composition having increased notched Izod impact strength and increased Gardner impact strength.
The increased impact strength of the compositions of the invention is unexpected because ethylene-propylene rubber when combined with a polybutadiene modified high impact styrene resin, results in a composition having decreased impact properties.
Accordingly, it is a primary object of this invention to provide impact resistant compositions of polyphenylene ether resins.